I modeled Cloud's Buster Sword based on screenshots from the upcoming remake of Final Fantasy VII. It's pretty darn big (slightly over 170 cm long), so I have split and keyed it which will probably help unless you have a very big printer ;)
The unsplit model is in there as well, in case you want to split it yourself.
There is room for a M8 threaded rod and nuts through the handle, the parry guard, and a bit of the blade in the cut version for some added strength.
I have now printed all of it and it works great. I forgot to put the materia mounts on in the picture, but they fit perfectly as well.